1. Field of the Invention
This invention relates to systems and methods for printing images and patterns on objects, members, and commodities such as musical instruments and furniture.
This application claims priority on Japanese Patent Applications Nos. 2003-423967, 2003-423945, and 2004-80942, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Conventionally, prescribed patterns are printed on members such as wooden arms (or side bars) of keyboard instruments having complicated shapes by one of, or by combination of, the following methods (1) to (5).    (1) Pattern printing by hot stamping.    (2) Vacuum adhesion of decorative sheets (or laminated sheets) having patterns such as vinyl chloride sheets and olefin sheets.    (3) Combination of polyester laminated sheets having patterns and DAP sheets.    (4) Direct printing by photogravure coaters.    (5) Direct printing by inkjet printers.
Japanese Patent Application Publication No. 2000-190462 discloses a printing method using an inkjet printer and watercolor ink for printing images on surfaces of wooden members with a high degree of fixation and high durability. Herein, an inkjet printer is used to directly transfer ink on surfaces of thick wooden members.
However, the aforementioned methods (1) to (5) suffer from the following problems.    (a) In the method (2), when multicolor printing such as photogravure printing is performed on a single sheet composed of vinyl chloride, olefin, and polyethylene terephthalate (PET), it is necessary to produce an expensive master (e.g., engraving and samplers), whereby printing is subjected to color correction and then actually performed on prescribed objects. For this reason, it takes a very long lead time (e.g., several months) and is very expensive (e.g., several millions of yen per master).    (b) In the methods (1) and (2) in which sheets are adhered onto prescribed objects, the degree of freedom in three-dimensional shaping and designing of objects should be reduced due to the restriction of adhesion.    (c) The method (3) does not provide a sense of unity with regard to patterns printed on objects.    (d) In the methods (1), (2), (4), and (5), when patterns are printed on objects having curved surfaces, patterns printed on curved surfaces may be partially extended and distorted, so that the decorative value may be degraded.    (e) The method (4), in which direct printing is performed using the photogravure coater, makes it possible to perform single-color printing or two-color printing only; hence, it is difficult to realize printing using various and colorful patterns. In addition, it is difficult to precisely reproduce colors even in simple patterns, that is, it is difficult to reproduce patterns with fidelity to original images.    (f) In the methods (1) and (2), when printing is performed on objects having three-dimensionally curved surfaces, it is difficult to adhere sheets onto three-dimensionally curved surfaces of objects. In this case, even when sheets are attached to three-dimensionally curved surfaces of objects, patterns may be distorted so as to give unnatural appearances.
Hereinafter, the aforementioned problem (d) in which patterns are partially extended and distorted will be described in detail.
With reference to FIGS. 7A to 7C, the phenomenon in which a printed pattern, which is printed on a prescribed object by using an inkjet printer, is partially extended and distorted will be described. FIG. 7A is a plan view showing a striped pattern of image data in which stripes are formed with equal distance therebetween. FIG. 7B is a cross-sectional view of an object 10 that is subjected to printing. FIG. 7C is a perspective view of the member 10 on which the pattern is actually printed. Herein, reference symbol I1 denotes the distance between stripes printed on a first surface 11 that is fiat, and reference symbol I2 denotes the distance between stripes printed on a second surface 12 that is slanted, wherein I1<I2. Reference numeral 200 denotes an axis lying in an ink ejecting direction by the inkjet printer.
The reference axis 200 lying in the ink ejecting direction of the inkjet printer is drawn in parallel with the normal axis lying in the normal direction of the first surface 11, while it is not drawn in parallel with the normal axis lying in the normal direction of the second surface 12 and the normal axis lying in the normal direction of a third surface 13. When the pattern in which stripes are formed with equal distance therebetween is printed on the object 10, the distance between the adjacent stripes is precisely maintained on the first surface 11, while the pattern should be partially extended and distorted on the second surface 12 and the third surface 13 due to their shapes.